<?xml version="1.0" encoding="utf-8"?>
<!--
Taxonomy based on XBRL standard Version 2.1.
Created by UBmatrix Automator Professional Edition 6.402.2172.25269 (2005-12-12 14:02).  
Contact www.ubmatrix.com
Software Copyright (c) 2002-2005 Universal Business Matrix inc., All Rights Reserved
Produced on 2005-12-12 14:08:50
-->
<schema xmlns="http://www.w3.org/2001/XMLSchema" xmlns:xbrli="http://www.xbrl.org/2003/instance" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:pei="http://www.conformance-dimensions.com/xbrl/inherited" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" targetNamespace="http://www.conformance-dimensions.com/xbrl/inherited" elementFormDefault="qualified" attributeFormDefault="unqualified">
  <annotation>
    <appinfo>
      <link:linkbaseRef xlink:type="simple" xlink:href="polymorphismErrorInherited-definition.xml" xlink:role="http://www.xbrl.org/2003/role/defintionLinkbaseRef" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:title="Definition Links, Hypercubes" />
    </appinfo>
  </annotation>
  <import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd" />
  <import namespace="http://xbrl.org/2005/xbrldt" schemaLocation="http://www.xbrl.org/2005/xbrldt-2005.xsd" />
  <import namespace="http://www.xbrl.org/dim/conf/primary" schemaLocation="../../lib/base/primary.xsd" />
  <element id="pei_Sales2" name="Sales2" type="xbrli:stringItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" abstract="true" nillable="true" />
</schema>
